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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.text.matcher;

import java.util.Arrays;

/**
 * A matcher class that can be queried to determine if a character array portion matches.
 * 

* This class comes complete with various factory methods. If these do not suffice, you can subclass and implement your * own matcher. * * @since 1.3 */ abstract class AbstractStringMatcher implements StringMatcher { /** * Class used to define a character for matching purposes. */ static final class CharMatcher extends AbstractStringMatcher { /** The character to match. */ private final char ch; /** * Constructor that creates a matcher that matches a single character. * * @param ch * the character to match */ CharMatcher(final char ch) { super(); this.ch = ch; } /** * Returns whether or not the given character matches. * * @param buffer * the text content to match against, do not change * @param pos * the starting position for the match, valid for buffer * @param bufferStart * the first active index in the buffer, valid for buffer * @param bufferEnd * the end index of the active buffer, valid for buffer * @return the number of matching characters, zero for no match */ @Override public int isMatch(final char[] buffer, final int pos, final int bufferStart, final int bufferEnd) { return ch == buffer[pos] ? 1 : 0; } } /** * Class used to define a set of characters for matching purposes. */ static final class CharSetMatcher extends AbstractStringMatcher { /** The set of characters to match. */ private final char[] chars; /** * Constructor that creates a matcher from a character array. * * @param chars * the characters to match, must not be null */ CharSetMatcher(final char[] chars) { super(); this.chars = chars.clone(); Arrays.sort(this.chars); } /** * Returns whether or not the given character matches. * * @param buffer * the text content to match against, do not change * @param pos * the starting position for the match, valid for buffer * @param bufferStart * the first active index in the buffer, valid for buffer * @param bufferEnd * the end index of the active buffer, valid for buffer * @return the number of matching characters, zero for no match */ @Override public int isMatch(final char[] buffer, final int pos, final int bufferStart, final int bufferEnd) { return Arrays.binarySearch(chars, buffer[pos]) >= 0 ? 1 : 0; } } /** * Class used to match no characters. */ static final class NoMatcher extends AbstractStringMatcher { /** * Constructs a new instance of NoMatcher. */ NoMatcher() { super(); } /** * Always returns false. * * @param buffer * the text content to match against, do not change * @param pos * the starting position for the match, valid for buffer * @param bufferStart * the first active index in the buffer, valid for buffer * @param bufferEnd * the end index of the active buffer, valid for buffer * @return the number of matching characters, zero for no match */ @Override public int isMatch(final char[] buffer, final int pos, final int bufferStart, final int bufferEnd) { return 0; } } /** * Class used to define a set of characters for matching purposes. */ static final class StringMatcher extends AbstractStringMatcher { /** The string to match, as a character array. */ private final char[] chars; /** * Constructor that creates a matcher from a String. * * @param str * the string to match, must not be null */ StringMatcher(final String str) { super(); chars = str.toCharArray(); } /** * Returns whether or not the given text matches the stored string. * * @param buffer * the text content to match against, do not change * @param pos * the starting position for the match, valid for buffer * @param bufferStart * the first active index in the buffer, valid for buffer * @param bufferEnd * the end index of the active buffer, valid for buffer * @return the number of matching characters, zero for no match */ @Override public int isMatch(final char[] buffer, int pos, final int bufferStart, final int bufferEnd) { final int len = chars.length; if (pos + len > bufferEnd) { return 0; } for (int i = 0; i < chars.length; i++, pos++) { if (chars[i] != buffer[pos]) { return 0; } } return len; } @Override public String toString() { return super.toString() + ' ' + Arrays.toString(chars); } } /** * Class used to match whitespace as per trim(). */ static final class TrimMatcher extends AbstractStringMatcher { /** * The space character. */ private static final int SPACE_INT = 32; /** * Constructs a new instance of TrimMatcher. */ TrimMatcher() { super(); } /** * Returns whether or not the given character matches. * * @param buffer * the text content to match against, do not change * @param pos * the starting position for the match, valid for buffer * @param bufferStart * the first active index in the buffer, valid for buffer * @param bufferEnd * the end index of the active buffer, valid for buffer * @return the number of matching characters, zero for no match */ @Override public int isMatch(final char[] buffer, final int pos, final int bufferStart, final int bufferEnd) { return buffer[pos] <= SPACE_INT ? 1 : 0; } } /** * Constructor. */ protected AbstractStringMatcher() { super(); } /** * Returns the number of matching characters, zero for no match. *

* This method is called to check for a match. The parameter pos represents the current position to be * checked in the string buffer (a character array which must not be changed). The API guarantees that * pos is a valid index for buffer. *

* The matching code may check one character or many. It may check characters preceding pos as well as * those after. *

* It must return zero for no match, or a positive number if a match was found. The number indicates the number of * characters that matched. * * @param buffer * the text content to match against, do not change * @param pos * the starting position for the match, valid for buffer * @return the number of matching characters, zero for no match */ public int isMatch(final char[] buffer, final int pos) { return isMatch(buffer, pos, 0, buffer.length); } }





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